| 摘要: |
| 群落中的养分储量及其空间分配格局对植物的养分利用效率以及生态系统的物质循环具有重要意义。西南干热河谷地区以其高温少雨的独特气候条件形成了稀树灌丛这一特殊的植被类型,为探讨该区域养分元素储量及其分配格局,该文以云南元江干热河谷稀树灌丛生态系统为研究对象,系统分析了氮(N)、磷(P)、钾(K)、钙(Ca)和镁(Mg)5种养分元素的储量及其分配格局。结果表明:(1)该群落中5种养分元素总储量为8.337 7 t·hm-2,其中Ca储量最高(2.587 8 t·hm-2),P储量仅为0.297 3 t·hm-2,与其他森林类型相比,各养分元素的储量均处于较低水平。(2)在垂直结构上,乔木层的养分储量占比最大(84.29%),其次是草本层(9.65%)和灌木层(5.69%),凋落物层仅占0.37%。(3)地下部分的养分储量比例高达47.81%。(4)干热河谷地区年降水量偏少且存在长达半年及以上的季节性干旱,这种极端环境条件显著限制了植物的生长发育。(5)为适应长期干旱胁迫,该区域稀树灌丛通过增加根系等地下部分的养分分配比例来维持生态适应性。该研究结果揭示了干热河谷生态系统中养分储量及其空间分配特征,为理解该地区生态系统的物质循环规律提供了重要依据,也为退化生态系统的恢复与重建提供了科学指导,更为深入探究干旱和半干旱区植物适应性策略和生态系统管理实践提供了重要参考。 |
| 关键词: 养分储量, 分配格局, 干热河谷, 干旱, 稀树灌丛 |
| DOI：10.11931/guihaia.gxzw202503037 |
| 分类号:Q948 |
| 文章编号:1000-3142(2026)02-0332-11 |
| Fund project:云南省重点研发计划项目(202403AC100028); 云南省中青年学术和技术带头人后备人才项目(202405AC350012); 中国科学院西双版纳热带植物园“十四五”科技创新规划项目(E3ZKFF2B01, XTBG-1450101)。 |
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| Nutrient storage and allocation pattern in a savanna ecosystem, Yuanjiang dry-hot valley, Southwest China |
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DAI Fangyu1,2, DAO Zhigang3, LI Zhenxue3, LI Zhongfei1, ZHANG Shubin2*
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1. Yunnan Key Laboratory of Plateau Wetland Conservation, Restoration and Ecological Services, School of Ecology and Environment,
Southwest Forestry University, Kunming 650224, China;2. Laboratory of Tropical Forest Ecology, Xishuangbanna
Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, Yunnan, China;3. Yuanjiang
National Nature Reserve Management and Conservation Bureau, Yuanjiang 653300, Yunnan, China
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| Abstract: |
| Nutrient storage and allocation patterns in plant communities are critical for understanding nutrient utilization and cycling within ecosystems. The dry-hot valleys of Southwest China, characterized by their extreme climatic conditions of high temperatures and low precipitation, support a unique savanna vegetation type. To investigate nutrient element storage and allocation patterns in this region, this study took the savanna ecosystem in the Yuanjiang dry-hot valley of Yunnan Province as the research object and systematically analyzed the storage and allocation patterns of five nutrient elements: nitrogen(N), phosphorus(P), potassium(K), calcium(Ca), and magnesium(Mg). The results were as follows:(1)The total nutrient storage of nitrogen(N), phosphorus(P), potassium(K), calcium(Ca), and magnesium(Mg)was 8.337 7 t·hm-2, with Ca having the highest storage(2.587 8 t·hm-2)and P having the lowest storage(0.297 3 t·hm-2). Compared to other forest ecosystems, nutrient storage in this savanna system was relatively low.(2)Vertically, nutrient distribution showed a clear hierarchy: the tree layer contributed the most(84.29%), followed by the grass layer(9.65%)and shrub layer(5.69%), with minimal contribution from the litter layer(0.37%).(3)Notably, belowground nutrient storage accounted for 47.81% of the total, indicating a significant allocation of nutrients to roots and other subterranean components.(4)The region's low annual rainfall and prolonged seasonal droughts imposed severe constraints on plant growth, leading to the observed low nutrient storage in this savanna ecosystem.(5)As an adaptive strategy to long-term drought stress, the savanna plants in this region allocate a greater proportion of nutrients to belowground structures such as roots to maintain ecological adaptability. This study reveals the characteristics of nutrient storage and spatial allocation in the dry-hot valley ecosystem, providing an important basis for understanding material cycling patterns in this region, scientific guidance for the restoration and reconstruction of degraded ecosystems, and valuable reference for in-depth exploration of plant adaptation strategies and ecosystem management practices in arid and semi-arid regions. |
| Key words: nutrient storage, distribution pattern, dry-hot valley, drought, savanna |
